Welker joins the Broncos' top two wide receivers from last season, Demaryius Thomas and Eric Decker, to form a trio of 1,000-yard pass-catchers. All three surpassed that mark in 2012, something that Welker has done in five of the last six seasons.

That wealth of talent at wideout isn't lost on Fox, and it won't go to waste with Peyton Manning at quarterback.

"When you're a passing attack and you've got (No. ) 18, you're looking for three productive guys out there," he said. "I think Wes Welker has proven as productive a slot receiver as there is really in recent NFL history."

Fox described Welker as a "tireless worker" with an "excellent feel for the game," and someone he's glad he doesn't have to gameplan against anymore when the Broncos take on the New England Patriots this season.

"He's a tough matchup," Fox said. "It's kind of a double signing. Defensively, we don't have to defend him anymore because he's on our team -- a little bit like when we got Peyton."

As far as the Broncos' entire free-agent crop to this point, Fox said the team is targeting players that he, Executive Vice President of Football Operations John Elway and the front office believe will make the team better. The goal is to "improve your football team," and Welker fits that bill.